Purpose: Patients with intermittent claudication are often prescribed a walking program to affect adaptations in peripheral blood flow. Although changes in blood flow with exercise have been well documented, few have used Doppler ultrasound technology to assess peripheral blood flow. This study sought to establish normative values of pedal blood flow for comparison with populations who have compromised circulation or vascular disease.

Subjects: Ten subjects, age 25 +/- 2 participated. All 10 subjects were without a history of vascular disease, were nonsmokers and clear of any conditions which would prevent moderate-intensity exercise.

Methods and materials: A Titan Ultrasound Doppler was used to make the following pedal artery measurements before and after a 20-minute episode of treadmill walking: artery width, time average mean flow (TAM), resistance index (RI), and acceleration index (ACC). Measurements were made at baseline, immediately after exercise, and at 5, 10, and 15 minutes of recovery.

Results: Immediately after exercise, the width of the pedal artery increased 34%, and time average mean flow increased 110%, while resistance index decreased 25%, and acceleration index decreased 21% compared to baseline values. Values had not returned to baseline levels at 15 minutes of recovery. Time average blood flow remained elevated by 56%.

Conclusion: Normal pedal artery response to moderate exercise includes vasodilation with a corresponding decrease in resistance and acceleration, and an increase in time average blood flow. These effects continue beyond 15 minutes of recovery. This study has provided normative Doppler ultrasound values which can be used for comparison in patients with vascular disorders.